The present invention relates to methods and apparatus for monitoring traffic to detect events or violations, such as speeding, and more particularly, to a method and apparatus for monitoring traffic events using vision-based recognition techniques.
Many law enforcement agencies must operate with insufficient financial resources or manpower (or both). Thus, such law enforcement agencies often have insufficient resources to effectively perform more routine tasks, such as enforcement of traffic violations. The irony, of course, is that increased enforcement of such traffic violations could lead to increased revenue for the law enforcement agencies or municipalities. In addition, studies suggest that the public perception of a reduced level of enforcement of traffic violations has led to an increase in the percentage of vehicles that routinely violate the traffic laws. For example, the percentage of all highway vehicles traveling at a speed above the posted limit is increasing at alarming rates.
A number of automated techniques have been proposed or suggested for monitoring vehicular traffic and detecting traffic violations. If successful, such automated techniques could (i) free up law enforcement personnel for more important tasks, such as investigation and prevention of crimes; (ii) generate increased revenue for the law enforcement agencies or municipalities; and (iii) increase the public perception that traffic laws will be diligently enforced, thereby reducing the percentage of vehicles violating the traffic laws and increasing public safety.
Most currently available traffic monitoring systems use sensors or other devices to detect traffic violations. For example, road-sensors embedded in the pavement or motion sensors can detect a vehicle traveling through an intersection after the traffic control signal has turned red. Likewise, a radar system can detect a vehicle traveling at a speed above the posted limit. Currently available traffic monitoring systems are often supplemented with one or more cameras to obtain images as evidentiary proof of the traffic violation. For example, a number of municipalities employ traffic monitoring systems that detect traffic violations and obtain an image of the vehicle, typically including the license plate number and, optionally, an image of the driver. An image is utilized purely to establish that the vehicle or driver was associated with the traffic violation.
While such traffic monitoring systems do (i) free up law enforcement personnel for more important tasks; (ii) generate increased revenue for the law enforcement agencies or municipalities; and (iii) increase the public perception that traffic laws will be diligently enforced, they suffer from a number of limitations, which if overcome, could greatly expand the utility and effectiveness of such traffic monitoring systems. Specifically, currently available traffic monitoring systems require the coordination of two distinct units, namely, the external sensor (or radar) and the image capture device. The installation of sensors in existing pavement or other locations, however, is often expensive or impractical. Furthermore, while the monitoring systems incorporate camera technologies, they fail to exploit additional information that can be obtained from the images.
A need therefore exists for a traffic monitoring system that uses vision-based technologies to recognize events and violations, such as speeding, directly from images of vehicular traffic. A further need exists for a traffic monitoring system that employs a rule-base to define each violation or event.
Generally, a method and apparatus are disclosed for monitoring traffic using vision-based technologies to recognize events and violations. The disclosed traffic monitoring system includes one or more image capture devices that are focused on a roadway where vehicles travel. The captured images are processed by the traffic monitoring system to identify one or more predefined events or traffic violations.
According to one aspect of the invention, a number of rules are utilized to define various traffic-related events, including traffic violations. Each rule contains one or more conditions that must be satisfied in order for the rule to be triggered, and, optionally, a corresponding action-item that should be performed when the rule is satisfied. At least one condition for each rule identifies a feature that must be detected in an image using vision-based techniques. Upon detection of a predefined traffic event, the corresponding action, if any, is performed by the traffic monitoring system. When the identified event is a traffic violation, for example, the corresponding action item may be the automatic issuance of a summons.
An illustrative traffic violation detection process is disclosed that processes the images obtained by the image capture devices to detect a number of specific, yet exemplary, traffic violations. In addition, a traffic event monitoring process is disclosed to illustrate the general concepts of the present invention. The disclosed traffic event monitoring process processes the captured images and detects one or more events defined by the traffic event rules.
A more complete understanding of the present invention, as well as further features and advantages of the present invention, will be obtained by reference to the following detailed description and drawings.